Cracking Bitcoins private keys generated from weak passphrases

not really looking out to make money with this. The main purpose was just learn more about how bitcoins works (specially about key and addresses generation)

Earlier attempts were more successful: (PDF) http://fc16.ifca.ai/preproceedings/36_Vasek.pdf

"Abstract. In the cryptocurrency Bitcoin, users can deterministically derive the private keys used for transmitting money from a password. Such "brain wallets" are appealing because they free users from storing their private keys on untrusted computers. Unfortunately, they also enable attackers to conduct unlimited online password guessing. In this paper, we report on the first large-scale measurement of the use of brain wallets in Bitcoin. Using a wide range of word lists, we evaluated around 300 billion passwords. Surprisingly, after excluding activities by researchers, we identied just 884 brain wallets worth around $100K in use from September 2011 to August 2015. We find that all but 21 wallets were drained, usually within 24 hours but often within minutes. We find that around a dozen "drainers" are competing to liquidate brain wallets as soon as they are funded. We find no evidence that users of brain wallets loaded with more bitcoin select stronger passwords, but we do find that brain wallets with weaker passwords are cracked more quickly."